The present invention relates to a method of reproducing a signal from a magneto-optical recording medium by reading out data bits (magnetic domains) through the magneto-optical interaction.
In a magneto-optical recording/reproducing method which forms data bits or bubble magnetic domains with irradiation of a laser beam to heat a recording medium locally and reads out the signal by utilizing the magneto-optical interaction, it is necessary, for increasing the magneto-optical recording density, to shorten the length of each bit length, i.e. to minimize the data magnetic domain. However, in the ordinary magneto-optical recording/reproducing system known generally, such attempt is limited by the wavelength of the laser beam in a reproducing mode, the numerical aperture of the lens and so forth for ensuring a satisfactory S/N in a reproducing operation. Under the current technical circumstances, for example, it is impossible to read out a data bit (magnetic domain) of 0.2 .mu.m with a laser beam having a spot diameter of 1 .mu.m.